RE: Performance Issues with AXIS & Axis Response Time appears lin ear with load

["Sutton, Ray" <Ra...@den.galileo.com>]

Hello, 

Not sure if you're seeing the same problem as me (see thread RE: Axis
Response Time appears linear with load) but here's what I discovered in case
it helps.

I'm seeing traffic backup behind a synchronized call in
org.apache.axis.XMLUtils at line 317 (entire method follows) 

    public static Document newDocument(InputSource inp)
        throws ParserConfigurationException, SAXException, IOException
    {
        DocumentBuilder db;
        synchronized (dbf) {
            db = dbf.newDocumentBuilder();
        }
        db.setEntityResolver(new DefaultEntityResolver());
        db.setErrorHandler( new ParserErrorHandler() );
        return( db.parse( inp ) );
    }


Now dbf is an instance of "javax.xml.parsers.DocumentBuilderFactory" which
is an abstraction layer around the chosen XML parser in my case it resolves
to "org.apache.crimson.jaxp.DocumentBuilderFactoryImpl"  the method called
under the  synchronized block is:

    public DocumentBuilder newDocumentBuilder()
        throws ParserConfigurationException 
    {
	DocumentBuilderImpl db = new DocumentBuilderImpl(this);
        return db;
    }

The constructor for DocumentBuilderImpl is doing a fair amount of work, time
constraints prevent me looking any deeper but I don't see any obvious need
for synchronization of this process.

What I suspect is that the good folks that develop Axis have synchronized
this because they can make no assumption about the implementation that
javax.xml.parsers.DocumentBuilderFactory abstracts. If this is the case then
I seems to me that the sync belongs in the DBF implementation not its
caller.

My personal instinct, unless anyone knows a good reason not, would be to
remove this specific synchronization point. 

Thanks

Ray Sutton
Systems Engineer

-----Original Message-----
From: Suket.N.Gandhi@wellsfargo.com [mailto:Suket.N.Gandhi@wellsfargo.com] 
Sent: Friday, October 03, 2003 2:09 PM
To: axis-user@ws.apache.org
Subject: Performance Issues with AXIS
Importance: High

Hi,

We are using Apache AXIS 1.1 to support a web service that returns images.
The images are base-64 encoded and embedded within the XML.
What we are seeing is very slow response times with AXIS when it tries to
construct the SOAP XML.The size of the images are in the range 50-100KB.

We are not sure if the large amount of data is the cause of the problem or
if we should be doing something else to overcome this problem ?

Thanks

Suket



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RE: Performance Issues with AXIS & Axis Response Time appears linear with load

[Robert Lowe <rm...@rmlowe.com>]

> My personal instinct, unless anyone knows a good reason not, would be to
> remove this specific synchronization point.

The docs are quite specific that a DocumentBuilderFactory is *not*
guaranteed to be thread-safe:

http://java.sun.com/j2se/1.4.2/docs/api/javax/xml/parsers/DocumentBuilderFac
tory.html

As noted in the docs, it's fine to have one DocumentBuilderFactory per
thread though.



Best regards,

Robert Lowe
http://RMLowe.com/